On the fidelity of DNA replication: herpes DNA polymerase and its associated exonuclease.
On the fidelity of DNA replication: herpes DNA polymerase and its associated exonuclease.
复制标题
关于 DNA 复制的保真度：疱疹 DNA 聚合酶及其相关的核酸外切酶。
作者：
J. Abbotts;Y. Nishiyama;S. Yoshida;L. Loeb
原核DNA聚合酶含有相关的3 '----5'外切核酸酶活性，其提供校对功能并对复制保真度有实质性贡献。真核疱疹型病毒的DNA聚合酶含有类似的相关核酸外切酶活性。我们已经研究了从野生型单纯疱疹病毒，以及从突变株和抗突变株纯化的聚合酶的保真度。在合成模板上，疱疹酶显示出比校正的原核DNA聚合酶更大的相对核酸外切酶活性和更大的切除末端错配碱基的能力。在phi X174天然DNA模板上，疱疹酶比纯化的真核DNA聚合酶更精确;错误率与E.大肠杆菌聚合酶I。然而，E.大肠杆菌聚合酶I对疱疹酶几乎没有影响。我们的结论是，这些病毒聚合酶是准确的，在没有校对，或检查的条件对疱疹DNA聚合酶的校对几乎没有影响。
Procaryotic DNA polymerases contain an associated 3'----5' exonuclease activity which provides a proofreading function and contributes substantially to replication fidelity. DNA polymerases of the eucaryotic herpes-type viruses contain similar associated exonuclease activities. We have investigated the fidelity of polymerases purified from wild type herpes simplex virus, as well as from mutator and antimutator strains. On synthetic templates, the herpes enzymes show greater relative exonuclease activities, and greater ability to excise a terminal mismatched base, than procaryotic DNA polymerases which proofread. On a phi X174 natural DNA template, the herpes enzymes are more accurate than purified eucaryotic DNA polymerases; the error rate is similar to E. coli polymerase I. However, conditions which abnegate proofreading by E. coli polymerase I have little effect on the herpes enzymes. We conclude that either these viral polymerases are accurate in the absence of proofreading, or the conditions examined have little effect on proofreading by the herpes DNA polymerases.